A woman’s body learns from difficulties in a first pregnancy and adapts to try to avert such difficulties in subsequent pregnancies, Israeli researchers said.

The researchers, at Hadassah Medical Center and the Hebrew University of Jerusalem, say their six-year study on the role of certain cells during a women’s pregnancy period may pave the way to develop new drugs to decrease complications in childbirth.

Their research on the “trained memory” of the “natural killer” cells that fight viruses and tumors, they said, found that the cells in charge of helping fetuses implant in the womb and avoid diseases ...